Turbochargers are used in engines to convert exhaust gas energy into boost provided to the intake system of the engine. Turbochargers may be used to increase the power output of engines or to downsize an engine while providing an equivalent amount of power as a larger naturally aspirated engine. In this way, the power output of the engine may be increased and/or the size of the engine may be reduced.
Turbocharger bearings are provided in turbochargers to support a turbocharger shaft and enable rotation of the shaft. Turbocharger bearings may have lower natural frequencies with higher displacements and deflections when the bearings have tolerances above a desired level and/or pre-loading below a desired level. As a result, noise, vibration, and harshness (NVH) is increased in the turbocharger, thereby increasing the likelihood of turbocharger degradation.
U.S. Pat. No. 6,048,101 discloses a bearing system including a spring positioned between two bearings, each bearing including a separate outer and inner race. The two bearings are spaced away from one another and the spring exerts a pre-load force on the separate bearings.
The inventor has recognized several drawbacks with the bearing assembly disclosed in U.S. Pat. No. 6,048,101. For example, the spring may increase the size and complexity of the bearing assembly. Moreover, it may be costly to manufacture two bearings.
The inventor herein has recognized the above issues and developed a bearing including a first set of rolling elements, a second set of rolling elements spaced away from the first set of rollers, a race at least partially enclosing the first and second sets of rolling elements, and a pre-loading element in the race between two outer sections of the race applying pre-load forces to the first and second set of rolling elements.
In this way, the pre-loading element may be integrated into the bearing race, thereby simplifying the assembly of the bearing. Further, locating the pre-loading element in the race between two outer sections to apply pre-load forces can reduce the complexity of the bearing when compared to bearings which may include additionally elements that provide a pre-loading force. As a result, the reliability of the bearing is increased and the manufacturing and/or repair cost of the bearing is reduced. The pre-loading element may also reduce the likelihood of thermal expansion of the bearing, and the resulting degrading effects of such expansion.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. Additionally, the above issues have been recognized by the inventor herein, and are not admitted to be known.